Patent Application
20220298878
The technical field generally relates to downhole setting tools for setting a downhole isolation device, such as a frac plug, in a well located in a subterranean hydrocarbon containing formation.
Setting tools can be used to set a downhole device, such as a frac plug, within a well located in a subterranean formation. The setting tool is generally coupled to the frac plug at the surface and the assembly is then run into a horizontal portion of the well, e.g., via wireline. The setting tool is then triggered such that it engages the frac plug to cause the frac plug to be anchored or “set” within the well. The frac plug seals off a portion of the well to facilitate multistage fracturing operations. After the frac plug has been set, the setting tool can be run out of the well so that it can be redressed and used with a subsequent frac plug. Using the setting tool over multiple runs, several frac plugs can be installed within a horizontal well in the context of multistage fracturing operations, for example.
Various types of setting tools can be used to set frac plugs. For example, a setting tool can have a mandrel with a chamber, and a barrel mounted around the mandrel such that upon ignition of a power charge within the chamber a pressurized gas can be generated to cause movement of the barrel over the mandrel so that the barrel can push a setting sleeve to engage the frac plug in the setting operation. An example of such a setting tool is described in U.S. Pat. No. 9,810,035, which is incorporated herein by reference in its entirety. There are still challenges in the operation and manufacture of such setting tools, and there is a need for enhancements in such downhole technologies.
Downhole setting tools with various features and enhanced functionalities are described herein.
In one example, there is provided a downhole setting tool for setting a frac plug, the downhole setting tool comprising: a mandrel having an upper end and a lower end, the mandrel comprising a chamber for housing expandable gas and a gas port in fluid communication with the chamber, the lower end of the mandrel being couplable to an upper end of a frac plug mandrel; a firing head secured to the upper end of the mandrel and configured for igniting a power charge to generate pressurized gas within the chamber; a barrel piston having a central bore configured for housing the mandrel, a lower end of the barrel piston being couplable to a sleeve for setting the frac plug; an expansion region defined between the mandrel and the barrel piston and being in fluid communication with the gas port so as to receive the pressurized gas, the expansion region being further defined by seals provided in between the mandrel and the barrel piston, thereby enabling the pressurized gas to exert force on the mandrel and the barrel piston to cause a stroke of the barrel piston over the mandrel as the expansion region expands axially; and a primary bleed system configured for downhole self-venting and comprising. The primary bleed system includes multiple bleed ports each extending through a wall of the barrel piston and being positioned so as to be isolated from the expansion region before generation of the pressurized gas and moving to be in fluid communication with the expansion region after the stroke allow pressurized gas to exit therethrough, the bleed ports being located on opposed sides of the barrel piston along a circumference that is perpendicular with a longitudinal axis of the barrel piston; bleed plugs disposed in respective bleed ports, each bleed plug comprising threads for threaded engagement with surfaces defining the bleed port and being composed of nylon, the bleed plugs being configured to blow out of the respective bleed ports after the stroke when the bleed ports come into fluid communication with the expansion region; and a circumferential undercut region provided in an inner surface of the barrel piston along the circumference on which the bleed ports are located, the circumferential undercut region facilitating the bleed ports to pass over at least one of the seals during assembly of the mandrel within the barrel piston.
In another example, there is provided a downhole setting tool for setting a downhole isolation device, the downhole setting tool comprising: a mandrel having an upper end and a lower end, the mandrel comprising a chamber for housing expandable gas and a gas port in fluid communication with the chamber, the lower end of the mandrel being couplable to an upper end of a frac plug mandrel; a firing head secured to the upper end of the mandrel and configured for igniting a power charge to generate pressurized gas within the chamber; a barrel piston having a central bore configured for housing the mandrel, a lower end of the barrel piston being couplable to a sleeve for setting the frac plug; an expansion region defined between the mandrel and the barrel piston and being in fluid communication with the gas port so as to receive the pressurized gas, the expansion region being further defined by seals provided in between the mandrel and the barrel piston, thereby enabling the pressurized gas to exert force on the mandrel and the barrel piston to cause a stroke of the barrel piston over the mandrel as the expansion region expands axially; and a primary bleed system comprising a bleed port extending through a wall of the barrel piston and a corresponding bleed plug disposed therein, the bleed port being positioned so as to be isolated from the expansion region before generation of the pressurized gas and moving to be in fluid communication with the expansion region after the stroke to blow out the bleed plug and allow pressurized gas to exit therethrough. The bleed plug includes: a head having a top surface configured to be flush with an adjacent outer surface of the barrel piston; a body comprising threads for threaded engagement with surfaces defining the bleed port; and wherein the bleed plug is composed of a polymeric material.
The downhole setting tool can have one or more optional features. For example, in some implementations, the polymeric material is nylon; the bleed plug has a generally cylindrical shape; the bleed plug is configured to extend within the bleed port and to terminate inset with respect to an inner surface of the wall of the barrel piston; the primary bleed system comprises multiple bleed ports and corresponding bleed plugs; the primary bleed system comprises two bleed ports and corresponding bleed plugs; the two bleed ports are arranged on opposed sides of the barrel piston at 180 degrees from one another; the bleed port comprises an undercut region at a proximal end thereof, and the bleed plug is sized and configured to terminate prior to the undercut region; the primary bleed system is configured to have a bleed port open area of 0.05 in2 to 0.12 in2; the primary bleed system is configured to have a bleed port open area of 0.06 in2 to 0.07 in2; the two bleeds ports each are sized to have an open area of 0.025 in2 to 0.04 in2; and/or the downhole isolation device is a frac plug.
In another example, there is provided a downhole setting tool for setting a downhole isolation device, the downhole setting tool comprising: a mandrel having an upper end and a lower end, the mandrel comprising a chamber for housing expandable gas and a gas port in fluid communication with the chamber, the lower end of the mandrel being couplable to an upper end of a downhole isolation device mandrel; a firing head secured to the upper end of the mandrel and configured for igniting a power charge to generate pressurized gas within the chamber; a barrel piston having a central bore configured for housing the mandrel, a lower end of the barrel piston being couplable to a sleeve for setting the downhole isolation device; an expansion region defined between the mandrel and the barrel piston and being in fluid communication with the gas port so as to receive the pressurized gas, the expansion region being further defined by seals provided in between the mandrel and the barrel piston, thereby enabling the pressurized gas to exert force on the mandrel and the barrel piston to cause a stroke of the barrel piston over the mandrel as the expansion region expands axially; and a primary bleed system comprising multiple bleed ports each extending through a wall of the barrel piston and each having a corresponding bleed plug disposed therein, the bleed ports being positioned so as to be isolated from the expansion region before generation of the pressurized gas and moving to be in fluid communication with the expansion region after the stroke allow pressurized gas to exit therethrough.
The downhole setting tool can have one or more optional features. For example, in some implementations, the multiple bleed ports are arranged around the barrel piston at a same longitudinal location there-along; the primary bleed system comprises two bleed ports and corresponding bleed plugs; the two bleed ports are arranged on opposed sides of the barrel piston at 180 degrees from one another; each or at least one of the bleed ports comprises an undercut region at a proximal end thereof; the bleed ports are identical to each other in shape, size and configuration; the bleed ports are formed by drilling through the wall of the barrel piston; the primary bleed system is configured to have a bleed port open area of 0.05 in2 to 0.12 in2; the primary bleed system is configured to have a bleed port open area of 0.06 in2 to 0.07 in2; each or at least one bleed port is sized to have an open area of 0.025 in2 to 0.04 in2; the bleed ports are defined by surfaces that have threads for receiving the bleed plugs which also have threads; the bleed ports are defined by surfaces that are generally smooth; and/or the downhole isolation device is a frac plug.
In another example, there is provided a downhole setting tool for setting a downhole isolation device, the downhole setting tool comprising: a mandrel having an upper end and a lower end, the mandrel comprising a chamber for housing expandable gas and a gas port in fluid communication with the chamber, the lower end of the mandrel being couplable to an upper end of a downhole isolation device mandrel; a firing head secured to the upper end of the mandrel and configured for igniting a power charge to generate pressurized gas within the chamber; a barrel piston having a central bore configured for housing the mandrel, a lower end of the barrel piston being couplable to a sleeve for setting the downhole isolation device; an expansion region defined between the mandrel and the barrel piston and being in fluid communication with the gas port so as to receive the pressurized gas, the expansion region being further defined by seals provided in between the mandrel and the barrel piston, thereby enabling the pressurized gas to exert force on the mandrel and the barrel piston to cause a stroke of the barrel piston over the mandrel as the expansion region expands axially; and a primary bleed system comprising a bleed port extending through a wall of the barrel piston and a corresponding bleed plug disposed therein, the bleed port being positioned so as to be isolated from the expansion region before generation of the pressurized gas and moving to be in fluid communication with the expansion region after the stroke to blow out the bleed plug and allow pressurized gas to exit therethrough, the bleed port passing over at least one seal during assembly of the mandrel within the barrel piston. The bleed port includes an inlet region in fluid communication with the expansion chamber after the stroke; an outlet region in fluid communication with the inlet region and with an atmosphere outside of the barrel piston; wherein the inlet region comprises an undercut surface that is tapered and continuous with an inner surface of the barrel piston to facilitate passing over the at least one seal during assembly.
The downhole setting tool can have one or more optional features. For example, in some implementations, the undercut surface is generally straight, and optionally has a chamfer that is optionally 10 to 20 degrees or 12 to 18 degrees; the undercut surface is generally concave; the undercut surface is generally convex; the undercut surface is about two to three times wider than a width of the outlet region; the undercut surface defines a grooved region that extends about a circumference of an inner surface of the barrel piston; the primary bleed system comprises multiple bleed ports that are located on the circumference; the multiple bleed ports are two bleed ports located at 180 degrees from one another; the primary bleed system comprises multiple bleed ports; the undercut surface defines a smooth and burr-less surface; and/or the downhole isolation device is a frac plug.
In another example, there is provided a downhole setting tool for setting a downhole isolation device, the downhole setting tool comprising: a mandrel having an upper end and a lower end, the mandrel comprising a chamber for housing expandable gas and a gas port in fluid communication with the chamber, the lower end of the mandrel being couplable to an upper end of a downhole isolation device mandrel; a firing head secured to the upper end of the mandrel and configured for igniting a power charge to generate pressurized gas within the chamber; a barrel piston having a central bore configured for housing the mandrel, a lower end of the barrel piston being couplable to a sleeve for setting the downhole isolation device; an expansion region defined between the mandrel and the barrel piston and being in fluid communication with the gas port so as to receive the pressurized gas, the expansion region being further defined by seals provided in between the mandrel and the barrel piston, thereby enabling the pressurized gas to exert force on the mandrel and the barrel piston to cause a stroke of the barrel piston over the mandrel as the expansion region expands axially; wherein the gas port extends perpendicularly with respect to a longitudinal axis of the setting tool.
The downhole setting tool can have one or more optional features. For example, in some implementations, the gas port comprises two co-linear gas conduits extending from opposed sides of the mandrel; the co-linear gas conduits are cylindrical; the co-linear gas conduits are in fluid communication with a lower end of the chamber of the mandrel; the lower end of the chamber of the mandrel has a conical shape; the co-linear gas conduits are in fluid communication with a lower region of the expansion chamber prior to gas pressurization; and/or the downhole isolation device is a frac plug.
In another example, there is provided a downhole setting tool for setting a downhole isolation device, the downhole setting tool comprising: a mandrel having an upper end and a lower end, the mandrel comprising a chamber for housing expandable gas and a gas port in fluid communication with the chamber, the lower end of the mandrel being couplable to an upper end of a downhole isolation device mandrel; a firing head secured to the upper end of the mandrel and configured for igniting a power charge to generate pressurized gas within the chamber; a barrel piston having a central bore configured for housing the mandrel, a lower end of the barrel piston being couplable to a sleeve for setting the downhole isolation device; an expansion region defined between the mandrel and the barrel piston and being in fluid communication with the gas port so as to receive the pressurized gas, the expansion region being further defined by seals provided in between the mandrel and the barrel piston, thereby enabling the pressurized gas to exert force on the mandrel and the barrel piston to cause a stroke of the barrel piston over the mandrel as the expansion region expands axially; a stroke indication system provided on the mandrel to indicate to an operator whether the barrel piston stroked a predetermined distance with respect to the mandrel.
The downhole setting tool can have one or more optional features. For example, in some implementations, the stroke indication system comprises a scribe line on the mandrel; the scribe line extends circumferentially around the mandrel; the scribe line is etched into the mandrel; the stroke indication system has a single scribe line; the stroke indication system comprises one or more indicia provided on the mandrel; the indicia are recessed with respect to an outer surface of the mandrel; the stroke indication system is configured to indicate whether bleed ports are positioned in fluid communication with the expansion chamber.
In another example, there is provided a downhole setting tool for setting a downhole isolation device, the downhole setting tool comprising: a mandrel having an upper end and a lower end, the mandrel comprising a chamber for housing expandable gas and a gas port in fluid communication with the chamber, the lower end of the mandrel being couplable to an upper end of a downhole isolation device mandrel; a firing head secured to the upper end of the mandrel and configured for igniting a power charge to generate pressurized gas within the chamber; a barrel piston having a central bore configured for housing the mandrel, a lower end of the barrel piston being couplable to a sleeve for setting the frac plug; an expansion region defined between the mandrel and the barrel piston and being in fluid communication with the gas port so as to receive the pressurized gas, the expansion region being further defined by seals provided in between the mandrel and the barrel piston, thereby enabling the pressurized gas to exert force on the mandrel and the barrel piston to cause a stroke of the barrel piston over the mandrel as the expansion region expands axially; an annulus defined between an upper part of the mandrel and a corresponding upper part of the barrel piston; a retainer cap configured to be secured into an upper end of the barrel piston and surrounding an upper portion of the mandrel; a liquid escape conduit configured to provide fluid communication with the annulus to enable liquid to escape the annulus during the stroke and volume reduction of the annulus.
The downhole setting tool can have one or more optional features. For example, the liquid escape conduit can include a groove in an inner surface of the retainer cap, and/or a groove in an outer surface of a portion of the mandrel surrounded by the retainer cap, for example. The total open area defined by a cross-section of the liquid escape conduit is between about 0.15 in2 and about 0.04 in2, between about 0.02 in2 and about 0.03 in2, or between about 0.022 in2 and about 0.028 in2.
In another example, there is provided a downhole setting tool for setting a downhole isolation device, the downhole setting tool comprising: a mandrel having an upper end and a lower end, the mandrel comprising a chamber for housing expandable gas and a gas port in fluid communication with the chamber, the lower end of the mandrel being couplable to an upper end of a downhole isolation device mandrel; a firing head secured to the upper end of the mandrel and configured for igniting a power charge to generate pressurized gas within the chamber; a barrel piston having a central bore configured for housing the mandrel, a lower end of the barrel piston being couplable to a sleeve for setting the frac plug; and an expansion region defined between the mandrel and the barrel piston and being in fluid communication with the gas port so as to receive the pressurized gas, the expansion region being further defined by seals provided in between the mandrel and the barrel piston, thereby enabling the pressurized gas to exert force on the mandrel and the barrel piston to cause a stroke of the barrel piston over the mandrel as the expansion region expands axially; wherein the barrel piston has a lower end with an outer diameter without a shoulder, the lower end being configured to be secured directly to an upper portion of a setting sleeve.
The downhole setting tool can have one or more optional features. For example, in some implementations, the lower end of the barrel piston comprises threads for be secured to corresponding threads of the setting sleeve; the setting can further include set screws inserted through corresponding apertures in the upper portion of the setting sleeve and the lower end of the barrel piston to prevent relative rotation therebetween; and/or the barrel piston is further configured so that the setting sleeve can be installed via the upper or lower ends of the barrel piston.
In another example, there is provided a frac plug setting assembly, comprising (i) a setting tool, comprising a mandrel having an upper end and a lower end, the mandrel comprising a chamber for housing expandable gas and a gas port in fluid communication with the chamber, the lower end of the mandrel being couplable to an upper end of a frac plug mandrel, wherein the upper end of the mandrel is configured for coupling to a firing head that enables igniting a power charge to generate pressurized gas within the chamber; a barrel piston having a central bore configured for housing the mandrel, a lower end of the barrel piston being couplable to a sleeve for setting the frac plug; an expansion region defined between the mandrel and the barrel piston and being in fluid communication with the gas port so as to receive the pressurized gas, the expansion region being further defined by seals provided in between the mandrel and the barrel piston, thereby enabling the pressurized gas to exert force on the mandrel and the barrel piston to cause a stroke of the barrel piston over the mandrel as the expansion region expands axially; optionally a retainer cap; (ii) an adapter kit, comprising a setting sleeve having an upper part coupled to the lower end of the barrel piston and a lower part; and a shear cap having an upper portion secured to the lower end of the mandrel, and a lower portion housed within part of the setting sleeve; and (iii) a frac plug, comprising a plug mandrel removably mounted to the lower portion of the shear cap; and a load member arranged in spaced relation with respect to the lower part of the setting sleeve, such that when the barrel strokes over the mandrel the setting sleeve engages the load member while the shear cap disengages from the plug mandrel in order to set the frac plug; wherein (a) the setting tool and the adapter kit are pre-assembled and made from carbon steel having a KSI of 35 to 60, (b) at least one of the mandrel, the barrel piston, and the shear cap is composed of a stronger carbon steel, while at least one of the setting sleeve and the retainer cap is composed of a weaker carbon steel; and/or (c) the carbon steel of the components has one or more of the following properties: a carbon content between 0.35 and 0.5 wt %); a tensile strength between 85,000 psi and 95,000 psi; a yield strength between 70,000 psi and 85,000 psi; an elongation in 2″ between 11% and 13%; a reduction in area between 30% and 37%; and a Brinell Hardness between 160 and 185; a carbon content between 0.15 and 0.25 wt %); a tensile strength between 60,000 psi and 70,000 psi; a yield strength between 50,000 psi and 60,000 psi; an elongation in 2″ between 14% and 16%; a reduction in area between 38% and 43%; and a Brinell Hardness between 120 and 130.
The downhole setting tool can have one or more optional features. For example, in some implementations, the carbon steel has a KSI of 40 to 60; the carbon steel has a carbon content between 0.15 wt % and 0.5 wt %; the carbon steel has a sulfur content up to 0.05 wt %; the carbon steel has a manganese content between 0.6 and 0.9 wt %; the mandrel and the barrel piston of the setting tool and the shear cap and the setting sleeve of the adapter kit are made from the same type of carbon steel; at least one of the mandrel and the barrel piston of the setting tool and the shear cap and the setting sleeve of the adapter kit is made from a different type of the carbon steel as the other components; the setting tool further comprises a retainer cap configured to be coupled to the barrel piston at an upper end thereof, and surrounding a part of the mandrel at an upper end thereof; the retainer cap is composed of carbon steel having a KSI of 35 to 60; at least one of the mandrel, the barrel piston, and the shear cap is composed of a stronger carbon steel, while at least one of the setting sleeve and the retainer cap is composed of a weaker carbon steel; the mandrel, the barrel piston, and the shear cap are composed of a stronger carbon steel, while the setting sleeve and the retainer cap are composed of a weaker carbon steel; in the stronger carbon steel has one or more of the following properties: a carbon content between 0.35 and 0.5 wt %; a tensile strength between 85,000 psi and 95,000 psi; a yield strength between 70,000 psi and 85,000 psi; an elongation in 2″ between 11% and 13%; a reduction in area between 30% and 37%; and a Brinell Hardness between 160 and 185; and the weaker carbon steel has one or more of the following properties: a carbon content between 0.15 and 0.25 wt %); a tensile strength between 60,000 psi and 70,000 psi; a yield strength between 50,000 psi and 60,000 psi; an elongation in 2″ between 14% and 16%; a reduction in area between 38% and 43%; and a Brinell Hardness between 120 and 130.
In another example, there is provided a method of setting a frac plug using a single-use disposable frac plug setting assembly, comprising: mounting a frac plug setting assembly as defined hereabove or herein to a wireline; deploying the frac plug setting assembly in a well via the wireline; igniting the power charge and generating an axial force against the setting sleeve to engage the frac plug and set the frac plug against a casing of the well thereby separating the frac plug from a sub-assembly comprising the setting tool and the adapter kit; removing the sub-assembly from the well; disengaging the sub-assembly from the wireline; and disposing of the sub-assembly.
In another example, there is provided a method for multistage fracturing of a reservoir comprising setting a downhole isolation device in a well using the downhole setting tool as defined herein and having one or more of the features described or illustrated in the present description. The method can also include subjecting the isolated well segment to a fracturing operation, and then repeating the isolation and fracturing for multiple segments along the well.
The methods can have various optional features, such as disposing of the sub-assembly comprises keeping the setting tool and the adapter kit attached together; mounting the frac plug setting assembly to the wireline comprises coupling the same to the firing head; disengaging the sub-assembly from the wireline comprises decoupling from the firing head for reuse; the axial force that is generated is at most 55,000 pounds, 50,000 pounds, 45,000 pounds, 40,000 pounds, 30,000 pounds, or 25,000 pounds; and/or the power charge in the firing head is provided to generate the axial force tailored for a pre-determined frac plug size and design.
Various techniques are described herein relating to a setting tool for setting a downhole isolation device, such as a frac plug, within a well. The setting tool can be of the type that uses a chamber in which pressurized gas can be generated to force a barrel piston to stroke with respect to the mandrel in order to set the frac plug.
Referring to
When a power charge is used to ignite the compound in the chamber and the pressurized gas is formed, the pressure will exert force between the mandrel 12 and the barrel piston 20 within the expansion region 22 and thereby cause the barrel piston 20 to first move downwardly with respect to the mandrel 12 as the expansion region 22 becomes longer in the axial direction. The setting tool's stroke begins with the barrel piston moving downward until the frac plug engages the casing, after which the barrel piston remains generally stationary and the mandrel moves upward due to the pressure in the expansion chamber 22. In one implementation, the expansion region 22 can have a generally annular shape as shown in
Still referring to
As the expansion region 22 expands and the barrel piston 20 strokes over the mandrel 12 in response to the pressurized gas, the barrel piston 20 pushes on an element coupled thereto in order to drive against the frac plug and cause it to set within the well casing. For example, an adapter can be used to functionally couple the frac plug to the setting tool 10 such that the downward force from the barrel piston 20 causes the frac plug to set. More regarding the adapter and the frac plug will be discussed further below.
Once the barrel piston 20 reaches a full stroke position, a primary bleed system 34 will come into fluid communication with the expansion region 22 and enables the pressurized gas to exit the expansion region in order to depressurize the setting tool 10. The primary bleed system 34 thus enables downhole self-venting after the full stroke of the barrel piston 20. The primary bleed system 34 can include a pair of bleed ports 36A, 36B that can be disposed through opposed sides of the barrel piston 20. More regarding the primary bleed system 34 will be described in further detail below.
Still referring to
The retention system 38 can be pre-calibrated to require a certain shear force for breaking. For example, the retention system 38 can be provided to shear only in response to pressures at or above about 6,000 lbs and below a maximum rating that would cause excessive pressure on the barrel piston depending on its construction and materials. For example, the shear rating can be between 6,000 lbs and 7,500 lbs, which facilitates enhanced retention while allowing the shearing to occur without damaging the barrel piston even when it is composed of less expensive and lower strength materials. Each shear screw can be rated at about 3,000 lbs, for example, such that a total force of 6,000 lbs is required to shear both shear screw 40A, 40B to enable the barrel piston to be released from and stroke over the mandrel 12.
The retention system 38 can be provided such that it enables relatively high security during run-in of the setting tool 10 to mitigate against accidental stroking of the barrel piston 20 and the mandrel 12. The retention system 38 can also be configured to become easily disengaged in response to the gas pressurization within the chamber 18. In some implementations, the retention system 38 is configured to shear above a threshold level between 6,000 lbs and 9,000 lbs, 6,000 lbs and 8,000 lbs, or 6,000 lbs and 7,000 lbs. When shear screws are used, they can be composed of metallic material such as brass.
The shear screws 40A, 40B can be provided through corresponding openings in a retainer cap 39 which is coupled to the barrel piston 20 as shown in
Referring now to
The stroke indication system 42 can also include a plurality of scribe lines or other indicia located along an intermediate section of the mandrel 12, where each scribe line or indicia provides a unique indication or otherwise enables an operator to quickly assess the stroke distance of the barrel over the mandrel. Since redressing the work string for redeployment down the well should be conducted as efficiently as possible, the stroke indication system 42 facilitates rapid assessment of whether a full stroke was completed downhole in the previous setting operation and whether self-venting has occurred.
In some implementations, the stroke indication system 42 includes static indicia, such as an etched line, shape, or the like at a pre-determined location along the mandrel 12. The etched line can extend around the circumference of the mandrel 12, or can be located along a segment of it, which can be 10%, 30%, 50%, 70% or more of the circumference. The etched line can be continuous and can be straight. It can also be perpendicular to the longitudinal axis of the mandrel. The etched line can alternatively be formed as a dotted or variable line. The etched line can vary along its length and, if it is oriented with a longitudinal component, it can include different features along its length to help indicate quantitatively or qualitatively the stroke distance that was completed. The stroke indication system 42 can include additional information, such as writing or numbers, to indicate to a user some information regarding the relative position of the barrel piston and the mandrel. The additional information can be etched into the material of the mandrel. The stroke indication system 42 can be provided so that it requires no resetting or manipulation by an operator to be functional for subsequent runs of the setting tool, as the case may be.
Referring now to
Referring to
By providing multiple bleed plugs in respective bleed ports, the primary bleed system facilitates prevention of debris from entering the setting tool during run-in while enhancing certainty for depressurization by mitigating the risk of one of the ports being blocked and also ensuring depressurization can occur faster which can, in turn, reduce the risk of deformation of the setting tool. The primary bleed system can thus have multiple bleed ports arranged and sized to promote these different functions. For instance, the bleed ports can be arranged equidistantly from each other (e.g., two ports 180 degrees from each other, three ports 120 degrees from each other, four ports 90 degrees from each other, and so on). The bleed ports can be arranged along a common circumference of the barrel piston, or alternatively at different longitudinal locations.
In addition, the bleed ports can be configured and sized to provide an advantageous total open area for the depressurization. For example, the bleed ports can each have an open area of 0.025 in2 to 0.04 in2 or 0.03 to 0.035 in2, and the total open area of the bleed ports can be 0.05 in2 to 0.12 in2, or 0.06 to 0.08 in2, for example. The bleed ports preferably each have a circular cross-section such that the bleed screw plugs can be screwed into the respective bleed ports during assembly. It was found that increasing the total open area of the bleed ports from about 0.03 in2 to about 0.06-0.07 in2 enabled a notable reducing in swelling of the barrel piston.
In addition, the bleed plugs 46 can be flush with the outer surface of the barrel piston 20 in order to avoid snagging on debris and/or other elements within the wellbore which could prematurely dislodge the bleed plugs 46. Alternatively, the bleed plugs could have other shapes and sizes such that they protrude above the outer surface of the barrel piston or are located below.
The bleed plugs 46 are preferably integrally composed of a polymer material, such as nylon, but may also have a composite structure. The threads 52 of the bleed plug 46 are configured to mate with corresponding threads of the bleed ports 36 to provide a secure connection during run-in while being deformed or sheared when under pressure from the pressurized gas in the expansion region after stroking. In the stroked position, the gas blows out at least one of the bleed plugs 46 for depressurizing the setting tool downhole.
Referring to
Referring to
Referring now to
It is also possible to provide multiple undercut grooves that are longitudinally spaced apart from each other and provide the undercut for bleed ports that are located at different positions along the length of the barrel piston. Indeed, various different patterns and arrangements of bleed ports and undercuts can be provided. Depending on the pattern of the bleed ports, the stroke indication system 42 can also be adapted to indicate the displacement of the barrel piston relative to the mandrel corresponding to different bleed port locations.
Referring back to
In addition, each gas port 24 can have a proximal end communicating with the chamber 18 and a distal end communicating with the expansion region 22. The proximal end can extend at least partly into a conical end section of the chamber 18, as shown in
Referring now to
In some implementations, the secondary bleed system 14 includes a secondary bleed passage 60 that is configured to be sealed during the downhole setting operation and then opened at surface to enable fluid communication between the chamber 18 and the atmosphere (e.g., when a firing head 62 is unscrewed from the upper end of the mandrel 12).
Referring now to
Referring to
Thus, once the seals 67 reach the conduit sections 65, the gas can flow through the conduit sections 65. The grooves 64 and the threaded portion on which they are provided can be configured and sized such that once the conduit sections 65 become in fluid communication with the chamber, the grooves 64 are also in fluid communication with the conduit sections 65 to enable depressurization. In this example, the secondary bleed passage 60 includes the conduit sections 65 and the grooves 64. It should be noted that the grooves 64 can come into fluid communication with the conduit sections 65 before, after or simultaneous when the conduit sections 65 fluidly connects with the chamber 18.
It is also noted that the there may be two, three or more conduits sections and grooves for forming the secondary bleed passage. For instance, the grooves can be distributed around the circumference of the upper end of the mandrel. By providing multiple grooves, the risk of blocking the passage can be reduced. Since the secondary bleed system is proximate to the firing head which produces solid char material, there is a risk that the solids could accumulate within the passage and inhibit depressurization. With a secondary bleed passage that includes multiple possible channels for fluid flow, the risk of blockage can be reduced. Each conduit section can be annular in shape, as illustrated in
The grooves 64 and the conduit sections 65 can be sized and configured to provide a desired depressurization rate. For example, the grooves 64 and the conduit sections 65 can be provided with pre-determined depths, configurations and sizes while ensuring the structural integrity of the threads and other components. Each groove 64 can be linear extending along the longitudinal axis of the setting tool. Alternatively, the secondary bleed passage 60 could be provided in other ways and can be configured to automatically become open when the firing head is decoupled from the upper end of the mandrel. For example, the firing head and the mandrel can be provided with channels that are misaligned to prevent fluid communication until, during decoupling of the firing head, they become aligned and enable depressurization.
Referring now to
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Referring now to
As shown in
The groove provided in the retainer cap 39 facilitates water exiting the annulus during the stroking of the barrel piston 20 with respect to the mandrel 12. During the stroke, incompressible water that has entered the annulus during deployment downhole become pressed as the volume of the annulus decreases. Compare the volume of the annulus shown in
The liquid escape conduit can be formed as a linear conduit, e.g., when the groove is provided lengthwise as a straight line. The size, shape and configuration of the liquid escape conduit can be provided based on the desired flow rate of water or other liquid escaping the annulus during stroking, and may depending on the strength of materials used to build the setting tool, the stroke rate, the power charge, and other factors. There may be a single groove, or multiple grooves that are parallel to each other, defining the liquid escape conduit.
In an alternative configuration, the liquid escape conduit can include a liquid bleed port provided through the barrel piston for allowing water to be released during stroking. The liquid bleed port could be provided just down from the retainer cap to communicate with the larger annulus portion.
In some implementations, the liquid escape conduit can be configured to reduce the risk of sand infiltration, which may be done by packing the liquid escape conduit at least partially with grease or another sand barrier compound. The sand barrier compound can be provided so that it can be expelled under pressure from the water within the annulus during stroking, but would otherwise tend to remain within the liquid escape conduit.
The liquid escape conduit can have a cross-sectional area or total open area facilitating release of liquid under pressure to avoid bowing or swelling of the barrel piston and other components of the setting tool. For example, the total open area defined by the groove cross-section can be between about 0.15 in2 and about 0.04 in2, between about 0.02 in2 and about 0.03 in2, or between about 0.022 in2 and about 0.028 in2. The flow area can be increased by such an amount compared to its initial flow area, which is allowed by the small amount of play in between the components. The total open area can also be designed based on the rate of volume reduction of the annulus.
Turning now to
Regarding the no-shoulder design illustrated in
In some implementations, there is provided a frac plug setting assembly, as example of which is shown in
Typically, adapter kits have been made of materials that are reusable, such that a same kit can be used multiple times to set multiple plugs downhole. In addition, adapter kits, frac plugs and setting tools are typically provided as distinct pieces of equipment that must be assembled on-site. Such assembly can lead to drawbacks if the user does not adhere to instructions. In addition, once the frac plug is set downhole and the setting tool and adapter kits are removed from the wellbore, disassembling the adapter kit from the setting tool at surface can lead to various inefficiencies. By providing the adapter kit, the setting tool and the frac plug as a pre-assembled unit, the unit can be deployed with high efficiency and reliability. In addition, constructing both the adapter kit and the setting tool using lower grade materials facilities disposal after use, as the components do not need to be decoupled from each other but can rather be disposed of as a single sub-assembly unit. No disassembly, inspection, maintenance or reassembly are required for the sub-assembly once it is removed from the wireline at surface.
The pre-assembling of the frac plug setting assembly can also facilitate greater surety when assembling the components together, notably as there is some degree of play between certain components and assembly can benefit from small, subtle adjustments. For example, the pre-assembly can facilitate ensuring that the appropriate gap between the setting sleeve 76 and the frac plug is provided. The gap should be appropriately sized to prevent pre-loading or side-loading that may increase the risk of pre-setting. Moreover, a primary benefit of the pre-assembly is that O-ring seals can b e installed in a controlled shop environment instead of on location at the well site, where installation is sometimes conducted in the middle of the night and by wireline employees that may or may not be skilled in the art of redressing and reassembling setting tools. Pre-assembly can facilitate increasing the reliability of the setting tool and allows the operator/wireline company the option of having lower employee requirements on location when a dedicated person would have been on location re-dressing setting tools. There is also a safety aspect to using a lighter weight pre-assembled single use setting tools versus the traditional heavy-duty reusable setting tools which can weigh over 100 lbs.
The frac plug setting assembly is thus pre-assembled using a setting tool and an adapter kit that are made from materials facilitating disposal. More regarding the low-grade materials will be discussed below.
In terms of construction materials, the setting tool and an adapter kit can be made using materials that are both low cost and good machineability. In some examples, the materials can include carbon steel rated at 35 to 65 kilopounds per square inch (KSI), 40 to 60 KSI or 45 to 55 KSI. Such steels can have a lower carbon content and a higher sulfur content than stronger steels typically used for downhole tools. For example, the steel can have a carbon content between 0.15 wt % and 0.50 wt %, the sulfur content can be up to 0.05 wt % or between 0.45 and 0.05 wt %, and a manganese content between 0.6 and 0.9 wt %. The carbon steel can be cold drawn.
In addition, the material can be tailored to each structural component of the frac plug setting assembly, including the mandrel, barrel piston, setting sleeve, shear cap, and retainer cap. For example, the barrel piston, mandrel and shear cap are the higher load components. The barrel piston benefits the most from stronger materials due to the swelling that can occur with pressure from the power charge. The barrel piston and the shear cap are also loaded in tensile during setting of the frac plug. In addition, the during the stroke the threads coupling the mandrel and the shear cap are under higher shear forces, and thus the materials should be selected accordingly. For example, the barrel piston, mandrel and shear cap can be composed of stronger low-grade material, while the setting sleeve and the retainer cap can be composed of a weaker low-grade material.
The stronger low-grade material can be a carbon steel having a higher carbon content (e.g., between 0.35 and 0.5 wt %), while the weaker low-grade material can be a carbon steel having a lower carbon content (e.g., between 0.15 and 0.25 wt %). The stronger low-grade material can be a carbon steel having one or more of the following mechanical properties: a tensile strength between 85,000 psi and 95,000 psi; a yield strength between 70,000 psi and 85,000 psi; an elongation in 2″ between 11% and 13%; a reduction in area between 30% and 37%; and a Brinell Hardness between 160 and 185.
The weaker low-grade material can be a carbon steel having one or more of the following mechanical properties: a tensile strength between 60,000 psi and 70,000 psi; a yield strength between 50,000 psi and 60,000 psi; an elongation in 2″ between 14% and 16%; a reduction in area between 38% and 43%; and a Brinell Hardness between 120 and 130.
While each of the mandrel, barrel piston, setting sleeve, shear cap, and retainer cap can be composed of the same carbon steel, one or more of such components can be made from different steel materials. In one example, one or both of the setting sleeve and the retainer cap are made from a weaker low-grade carbon steel, which can be the same or different type of carbon steel; while the other components are made from a stronger low-grade carbon steel, which can also be the same or different types of steel. It is also noted that one or more of these components (e.g., the barrel piston) could be made from a medium- or high-grade material that has improved mechanical properties compared to the stronger low-grade material described above.
It is also noted that certain features as described herein, such as the liquid escape conduit, can facilitate the use of lower grade materials for certain components. In the case of the barrel piston, when the liquid escape conduit is used it can allow the pressurized fluid to escape more easily and thus reduces the force exerted on the barrel piston, which in turn reduces the risk of swelling. Thus, the barrel piston can use a weaker material when the liquid escape conduit is provided.
The main components composed of such lower grade steel would be the mandrel, the barrel piston and the retainer cap of the setting tool; and the shear cap and the setting sleeve of the adapter kit. The adapter kit can be adapted for mounting to the shoulderless barrel piston, but could also be adapted with an adjusting nut, where the adjusting nut is preferably also made using lower grade materials. It is also noted that the main components mentioned above can be made from the same low-grade carbon steel, or different low-grade carbon steel materials depending on the functionality and machinability that may be desired.
In operation, a wireline crew may receive the frac plug setting assembly as a single unit and mounts it to the wireline for deployment. The assembly is then run into the well and the frac plug is set in the desired location. The sub-assembly (minus the frac plug) is then run out of the well, removed from the wireline and the firing head, and can be disposed of immediately as scrap material. The firing head can be composed of higher-grade materials, and can be reused with the subsequent frac plug setting assembly, although he firing head could be disposed with the rest of the sub-assembly. The frac plug setting assembly can be provided excluding the firing head, in which case it can mounted to the firing head on site, or it could be provided pre-assembled with the firing head, if desired.
The present application is a continuation of U.S. application Ser. No. 16/795,042, filed Feb. 19, 2020, which is a continuation of U.S. application Ser. No. 16/288,900, filed Feb. 28, 2019, which is a continuation of U.S. application Ser. No. 16/284,717, filed Feb. 25, 2019, which claims the benefit of U.S. Provisional Application Ser. No. 62/743,716, filed Oct. 10, 2018 and U.S. Provisional Application Ser. No. 62/776,503, filed Dec. 7, 2018, all of which applications are hereby incorporated by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62743716 | Oct 2018 | US | |
| 62776503 | Dec 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16795042 | Feb 2020 | US |
| Child | 17828710 | US | |
| Parent | 16288900 | Feb 2019 | US |
| Child | 16795042 | US | |
| Parent | 16284717 | Feb 2019 | US |
| Child | 16288900 | US |
